Would love some guidance if possible. 

So, I think you can expect interest rates of 8% right now or possibly more. 4.

I’d think long and hard about this and possibly set up financial parameters for who is responsible.

RE is a long term play.

Is it possible to sell or refinance one unit to pay the other off completely. 

Contractors stated that he does surface level cosmetic fixes as fast as possible to pass inspections.

Is it possible for her to buy the house/land then we subdivide the property (property has an approved preliminary plat for subdivision into 2-3 separate lots, electrical and pluming lines have been put in place for future development).

The department of justice filed a request to eliminate the comp agreement requirement due to possible anti trust violations.  

HELOCs are much tricker than a closed end second - they don't typically allow you to close in an LLC and they are full doc qualification, meaning your FICO, employment history, income, DTI etc all come into play.

It's a little harder to cashflow here in San Diego, but it's possible with the right team in place!